New research has revealed that human hunters were not to blame for the extinction of the woolly rhinoceros and they were instead wiped out by climate change. Researchers from Stockholm University came to this conclusion by studying DNA that was extracted from 14 fossils belonging to woolly rhinos (several pictures can be seen here).
Even though over-hunting did affect the populations of some large animals like cave lions and woolly mammoths, this new research indicates that global warming had an even bigger effect on the demise of woolly rhinos. One of the authors of the study, Professor Love Dalén, explained that evidence of humans living in Siberia around 30,000 years ago had very little to do with the species’ extinction by stating that “the decline towards extinction of the woolly rhinoceros doesn't coincide so much with the first appearance of humans in the region. If anything, we actually see something looking a bit like an increase in population size during this period.”
The experts agreed that the population of woolly rhinos were “stable and diverse” in Siberia up until just a few thousand years before they became extinct. They believe that the warmer temperatures from a period called the Bølling-Allerød interstadial were too much to handle for the cold-adapted species.
Studies on the fossilized remains allowed the experts to “look back in time” in addition to estimating the species’ population numbers up to tens of thousands of years prior to them disappearing. Co-author, Dr. Nicolas Dussex, went into further details, explaining, “We found that after an increase in population size at the start of a cold period some 29,000 years ago, the woolly rhino population size remained constant and that at this time, inbreeding was low.”
Based on the fact that the earliest evidence of humans in that area is from 30,000 years ago and that the woolly rhinos had a stable population far after that, it’s safe to say that hunting did not lead to their demise. Another co-author, Edana Lord, stated, “That's the interesting thing: we actually don't see a decrease in population size after 29,000 years ago,” adding, “The data we looked at only goes up to 18,500 years ago, which is 4,500 years before their extinction, so it implies that they declined sometime in that gap.” The experts are now hoping to get DNA from woolly rhinos that were around during that important 4,500-year time period in order to know for sure what exactly killed them off.
Lord finished off by stating, “We're coming away from the idea of humans taking over everything as soon as they come into an environment, and instead elucidating the role of climate.” “Although we can't rule out human involvement, we suggest that the woolly rhinoceros' extinction was more likely related to climate.” Their study was published in the journal Current Biology and can be read in full here.